Evidence Supports Two Types of Heart Failure, Report Wake Forest University Baptist Medical Center Researchers
WINSTON-SALEM, N.C. – New evidence supports the existence of a second type of congestive heart failure in which the heart contracts normally but doesn’t fill with enough blood, report researchers from Wake Forest University Baptist Medical Center in this week’s Journal of the American Medical Association.
“There has been a debate among doctors about whether patients with this newly recognized disorder truly have heart failure,” said Dalane W. Kitzman, M.D., a Wake Forest cardiologist. “That is because there is no simple means to diagnose it and its symptoms could have other causes. This confusion has kept some patients from getting treatment and prevented researchers from finding the most effective way to treat the disorder.”
In a study of 147 participants, researchers compared patients with the newly recognized form of heart failure to healthy normal subjects and also to patients with the classic form of heart failure. They measured exercise capacity, quality of life and hormone levels – areas that have long been accepted as hallmarks of congestive heart failure.
Researchers found that compared to the healthy normal subjects, patients with the newly discovered type of heart failure had severely reduced exercise capacity and quality of life and increased hormone levels. These changes were similar to those measured in patients with the classic form of heart failure
“Our research indicates that this newly recognized disorder is a true second form of heart failure,” said Kitzman. “We have recently shown that it is associated with a substantial burden of excess disability and death in older Americans. This disorder should be the focus of intensive research.”
With the more widely known type of congestive heart failure – systolic heart failure – the heart doesn’t contract strongly enough. With the newly recognized type – diastolic heart failure – the heart’s main chamber doesn’t fill with enough blood, probably because the heart is stiffer than normal. The end result of both types is that the body doesn’t get enough oxygenated blood to meet its demands.
“The participants with diastolic heart failure were essentially the same as the systolic group in the domains that doctors have agreed characterize typical heart failure,” said Kitzman. “We believe these results help establish this as a second type of heart failure.”
Kitzman said the controversy about heart failure resulted because while systolic heart failure is easily diagnosed with an ultrasound test to measure the heart’s squeezing ability, there is no single test to diagnose diastolic heart failure. In addition, the main symptoms of diastolic heart failure, shortness of breath and fatigue with exertion, can also be caused by a variety of other conditions such as heart artery or valve disease, lung disease, aging, or obesity.
“When patients have symptoms of heart failure and ultrasound shows a heart that contracts normally, doctors have doubted their own diagnostic abilities and have been reluctant to put these patients on heart failure treatment,” said Kitzman.
There is no standard for diagnosing diastolic heart failure. For the research study, the diagnosis was made by ruling out the other medical conditions that could cause its symptoms.
The research was supported by the National Institute on Aging, part of the National Institutes of Health. Investigators at the Department of Health and Exercise Sciences at Wake Forest University helped conduct the research.
"This research is critically important for helping us characterize a condition that is common among older people," says Andre Premen, Ph.D., of NIA''s Geriatrics and Clinical Gerontology Program. "It provides clear evidence that isolated diastolic heart failure is a distinct syndrome and may need to be addressed as such. We look forward to moving toward clinical research to test whether treatments that have proven effective for systolic heart failure, or other new therapies, might be effective against diastolic heart failure."
Congestive heart failure is the leading cause of hospitalization in older patients. Previous research from Kitzman and colleagues showed that more than half of older adults with heart failure have the second form of the disorder, known as diastolic heart failure.
Because there has been little research into treating diastolic heart failure, doctors don’t yet know if the same treatments used for systolic heart failure (diuretics and medications to expand the blood vessels or increase the force of the heart’s contractions) will be effective. Researchers at Wake Forest are currently evaluating treatments for diastolic heart failure, including exercise and investigational drugs. ###
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